Expanding the Genetic Code

We are exploring the application of unnatural base pairs as an expansion of the genetic code. To prevent loss of unnatural base pairs during replication, we will utilize several systems including CRISPR/Cas9. The expanded genetic code allows for the ribosomal incorporation of multiple non-canonical amino acids (ncAAs) into peptides. With their broad chemical and functional diversity, ncAAs provide a variety of promising applications including protein labeling, photocaging, structure analysis, and specific protein interactions. Therefore, our innovative toolkit for the translational incorporation of ncAAs in E. coli is a valuable contribution to iGEM. Directed evolution of tRNA/aminoacyl-tRNA synthetase pairs enables the site-specific incorporation of ncAAs into peptides. This approach results in an optimal orthogonality to the autologous translation apparatus and a high flexibility concerning the incorporation of multiple ncAAs. As proof of concept, we are developing a rapid test for prions and a new chromatography method for mild protein elution.